The electroencephalographic characteristics of mental fatigue, which was induced by long-term working memory task of 2-back, were studied by event-related potential (ERP) technology in order to obtain objective evaluation indicators for mental fatigue. Thirty-two healthy male subjects, 22–28 years old, were divided into two groups evenly, one is un-fatigue group and the other is fatigue group. The fatigue group performed a 2-back task for 100 min continuously, while the un-fatigue group just performed a 2-back task at the first and last 10 min respectively, and rested during the middle 80 min. The subjective levels of fatigue, task performance and electroencephalogram were recorded. The impaired thought and attention states, enhanced sleepy and fatigue feeling were found in the fatigue group, meanwhile their reaction time to 2-back task extended, and the accuracy decreased significantly. These results verified the validity of mental fatigue model induced by 2-back task, and then the ERP characteristic parameters were compared and analyzed between fatigue group and un-fatigue group. The results showed that the fatigue group’s amplitudes of P300 (F = 2.539, P < 0.05) and error-related negativity (ERN) ( F = 10.040, P < 0.05) decreased significantly along with the increase of fatigue comparing with the un-fatigue group, however, there were no significant change in other parameters (all P > 0.05). These results demonstrate that P300 and ERN can be considered as potential evaluation indictors for mental fatigue induced by long-term working memory task, which will provide basis for the future exploring of countermeasure for mental fatigue.
Objective To study the anatomy and variations of hepatic veins draining into inferior vena cava （IVC）， and to classify the surgical techniques of piggyback liver transplantation （PBLT） based on the view of hepatic veins anatomy with IQQA liver image analysis system so as to provide the important basis for the perioperative clinical decision making. Methods Two hundred and forty-eight cases of PBLT were preformed in the Zhongnan Hospital of Wuhan University and the 3rd Xiangya Hospital of Central South University from May 2000 to August 2007， the types of hepatic veins were summarized according to the anatomy of hepatic veins and short hepatic veins draining into IVC at the second and third hepatic hilars. Forty cases of PBLT were preformed in the Zhongnan Hospital of Wuhan University from March 2010 to April 2013， and the anatomy of hepatic veins was reviewed with IQQA liver image analysis system. The anatomy of hepatic veins and technological type of liver transplantation were recorded respectively. Results Of these 248 livers studied in our center， type Ⅰ（the left and middle hepatic vein joined as one trunk ） was found in 142 cases （57.25%）， type Ⅱ （the right and middle hepatic vein joined as one trunk） was 54 cases （21.77%）， type Ⅲ （three hepatic veins joined as one trunk） in 14 cases （5.64%）， type Ⅳ （the left， middle， and right hepatic veins were all unique）in 34 cases （13.71%）， and type Ⅴ （no hepatic veins but short hepatic veins） in 4 cases （1.61%）. The data of 40 cases of PBLT from IQQA liver image analysis system showed that type Ⅰwere found in 24 cases （60.00%）， type Ⅱin 9 cases（22.50%）， type Ⅲ in 2 cases （5.00%）， type Ⅳ in 4 cases （10.00%）， and type Ⅴ in 1 case （2.50%）， which were matched with hepatic vein classification standard of the author. Conclusions Studying the anatomy and variations of hepatic veins draining into IVC with IQQA liver image analysis system and classifying the surgical techniques of PBLT （type Ⅰ，Ⅱ，Ⅲ，andⅣA patients can be performed classical PBLT；Type ⅣB and Ⅴ patients can only be performed ameliorative PBLT） could provide an important basis for clinical preoperative decision.
Objective To explore the protective effect and mechanism of Astragalus polysaccharides (APS) on liver injury in the state of brain death in New Zealand rabbits. Methods Twenty-four New Zealand rabbits were randomly divided into 3 groups (n=8): the blank control group, the brain death group, and the APS group. We obtained blood and liver tissue specimens from rabbits of three groups at 4 h and 8 h after treatment respectively (n=4). The rabbits of blank control group simulated the procedures of anesthesia and surgery of the brain death, without the Foley balloon catheter being pressurized, and maintained anesthesia. The brain death group: brain-dead models were established. The APS group: injection of APS (12 mg/kg) via the femoral vein bolus immediately after anesthesia, brain-dead models were established as same as rabbits of brain death group. The blood and liver tissue samples were taken at 4 h and 8 h after treatment to detect aminotrans-ferase (AST), alanine amino-transferase (ALT) and tumor necrosis factor α (TNF-α), and to observe the change of liver tissue by HE staining and immunohistochemical staining〔expression level of nuclear transcription factor p65 protein (NF-κB p65) could be detected by immunohistochemical staining〕. Results ① ALT and AST. Compare with the blank control group at the same time (4 h and 8 h), levels of ALT and AST in brain death group and APS group were significantly increased (P<0.05), and the levels of ALT and AST in brain death group were higher than those of APS group at each time point (P<0.05). In the same group, compared with 4 h, there was no significant difference in the levels of ALT and AST in blank control group at 8 h (P>0.05); the levels of ALT and AST in brain death group at 8 h were both higher than those of 4 h (P<0.05); the levels of ALT at 8 h in APS group was higher than that of 4 h, but there was no significant difference in the level of AST between 4 h and 8 h (P>0.05). ② TNF-α. Compare with the blank control groups at same time (4 h and 8 h), levels of TNF-α in brain death group and APS group were significantly increased(P<0.05), and level of TNF-α in brain death group was higher than that of APS group at 4 h and 8 h (P<0.05). ③ The HE results. The liver tissue structure of blank control group, brain death group, and APS group at 4 h had no obvious change. The liver tissue structure of brain death group at 8 h showed the evident tissue damage: liver cells showed the balloon samples, disordered arrangement, cytoplasmic loose light dye net-like, and inflammatory cells infiltrated in portal area. The liver tissue structure of APS group at 8 h showed that, liver cells showed mild edema, normal arrangement, and a small amount of inflammatory cells infiltrated in portal area. The liver tissue structure damage of APS group at 8 h was milder than that of brain death group. ④ Immunohistochemical staining results. There was no significant difference in expression levels of NF-κB p65 protein among blank control group, brain death group, and APS group at 4 h (P>0.05). But at 8 h, the expression levels of NF-κB p65 protein in brain death group and APS group were higher than that of blank control group (P<0.05), and the expression level of NF-κB p65 protein in brain death group was higher than that of APS group (P<0.05). The expression levels of NF-κB p65 protein in brain death group and APS group at 8 h was higher than that of 4 h in the same group (P<0.05), but there was no significant difference between 4 h and 8 h in blank control group (P>0.05). Conclusions Brain death will cause liver damage and the injury degree may be related to the continuous time. The damage at 8 h was more serious than that of 4 h. APS has a protective effect on liver of brain-dead rabbits' and its mechanism may be closely related to inhibit TNF-α and NF-κB by diverse ways to reduce the inflammation of the liver injury.